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Voltage Divider IC's

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soundboy.massacre
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Voltage Divider IC's

Post by soundboy.massacre »

Who's got a recommendation for their favorite Voltage Divider IC?
I don't really need more than 1 or 2 octave down capability, but would like to know what else is out there that sounds good, tracks well etc...
Thx
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valis
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Post by valis »

That's a good question. I just use a simple CD4040 but the inputs have to be squares for it to work properly.
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widdly
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Post by widdly »

I don't think that "Voltage divider" is the right name for what you want.

The sh-101 uses a CD4013 and it's setup to give you different pulse widths for the sub octaves. Other than the pulse width, I would think all the CMOS chips would sound the same and would track 100%.

For a really elaborate option, check out the CGS sub octave circuit.
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andrewF
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Post by andrewF »

Frequency or octave divider would be a better term
If you just want one or two oct down look at something with a 4013 otherwise
The Polyfusion one on Exp. Anon. looks pretty good

HERE
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valis
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Post by valis »

Nice post Andrew. Out of curiosity, what does "n/c" mean at the output 4136a (top middle of schematic)? Is that "not connected?"
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lazerkind
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Post by lazerkind »

n/c usually stands for no connection = floating = not connected to anything
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valis
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Post by valis »

:tu:
soundboy.massacre
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Post by soundboy.massacre »

OK, then I can get 2 octaves down from daisy-chaining both halves of the 4013, or up to 7 octaves down from the 4024..but the clock input has to be square on both of them for it to work properly
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daverj
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Post by daverj »

The pair of amps in the upper left of the schematic shown above converts an analog CV or audio into the square wave needed by the divider chips.
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Dr. Sketch-n-Etch
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Re: Voltage Divider IC's

Post by Dr. Sketch-n-Etch »

soundboy.massacre wrote:Who's got a recommendation for their favorite Voltage Divider IC?
Yeah... they're called resistors! :lol:
(Sorry for the snarkiness; I just couldn't... RESIST! :lol: :lol: :lol: :deadbanana:
We've moved fast. We need love. A part we offer is our only freedom.
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andrewF
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Post by andrewF »

soundboy.massacre wrote:OK, then I can get 2 octaves down from daisy-chaining both halves of the 4013, or up to 7 octaves down from the 4024..but the clock input has to be square on both of them for it to work properly
yes, but that is what the two op amp stages at the upper left are doing. The 1st is an inverting buffer, the second is a comparator which outputs a signal the CMOS chips will be very happy to deal with.
These days it is common just to have the comparator stage set to react when an input signal crosses, say, 1.5V. Then you can use almost any audio rate signal on the input.

Check out the "clock in" part of the schematic on Ken's Gated Comparator. The 100k/15k connected to pin 6 set the voltage the input is compared to, in this case 1.96V. You also need to add the diode and 100k to ground coming from pin 7 of the op amp. The diode ensures the CMOS only sees positive voltages and the 100k ties the CMOS input to ground when no signal is present, otherwise it 'floats' and starts to muck around like a bored puppy.
BTW just referring to the Gated Comp as an example, you will need different CMOS for your purposes.
soundboy.massacre
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Post by soundboy.massacre »

thanks for the info on gating a comparator
i'm interested in how two resultant square waves two or more octaves apart can be ring modulated using XOR function (NAND gates)???
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E.A.S.
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Post by E.A.S. »

andrewF wrote:Frequency or octave divider would be a better term
If you just want one or two oct down look at something with a 4013 otherwise
The Polyfusion one on Exp. Anon. looks pretty good
This circuit works great. I've built it probably ten times over the years.
if you build it, stick with a standard pinout op-amp. not the weird 4136.
I've used both, but these days it makes more sense to stick with 'normal' pin-outs.
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